It is known to remove material from a metallic workpiece (see German Patent Disclosure Document DE-OS No. 26 33 629) by using a work tool to produce an opening in a metallic workpiece. It has also been proposed to use an electrochemical method (see German Patent Disclosure Document DE-OS No. 28 24 770) to produce bevels at the edges of slits of engine cylinders for reciprocating engines. In this method, the cylinder walls are first coated with a hardening chrome layer, and the regions adjacent to the slit edges are deburred and rounded electrochemically.
It is also well known to process metallic workpieces by electrochemical workpiece removal. After empirical determination of the shape of the tool electrode and of working conditions, a precisely shaped and predetermined recess or cavity can be obtained in the workpiece. This process is relatively expensive. The operation is carried out with very high operating current and electrolyte pressures. Small operating gaps are used and thus there is a danger of electrical shorting during the electrochemical etching, which can cause damage due to the high operating current.